Jay Levy and his family took their iPhones on a Mediterranean cruise. Now the Hewlett Harbor entrepreneur feels as if he got taken for a ride, receiving a 54-page monthly bill of nearly $4,800 from AT&T Wireless. While Levy, his wife and his daughter were enjoying the trip, and even while they were sleeping, their three iPhones were racking up a bill for data charges. The iPhone regularly updates e-mail, even while it's off, so that all the messages will be available when the user turns it on.

Always read the fine print.